Hickman's knotweed

Herbs, compact, often cushion-like. Stems erect, color unknown, simple to profusely branched from near base, not wiry, 2-5 cm, glabrous. Leaves persistence and crowded at brance tips, not articulated to ocreae; ocrea 4-6 mm, glabrous, proximal part cylindric, distal part silvery, disintegrating nearly to base into straight fibers; petiole absent; blade 3-veined, without pleats, linear, 5-35 × 1-1.5 mm, margins revolute, smooth, apex acuminate. Inflorescences axillary; cymes insertion unknown, 1-flowered. Pedicels absent. Flowers closed; perianth 2-3 mm; tube 6-18 % of perianth length, tepals imbrication unknown, white with whitish or pink margins, petaloid, oblong, apex acute, mucronate; midveins unbranched; stamens 8; anthers orange-pink. Achenes enclosed in perianth, olive brown, ovate, 2-2.3 mm, faces subequal, shiny, smooth.

Flowering May-Oct. Open, seasonally dry grasslands; of conservation concern; 200-300 m; Calif.

The above description is based on the original one by Hinds and Morgan. Polygonum hickmanii is known only from the northern end of Scotts Valley in Santa Cruz County.